= Solution
For the <ultrarelativistic magnetic bending radius>, the <Lorentz force> supplies the transverse <momentum> change, so $r=p/(eB)$. At this energy the proton is ultrarelativistic, giving $pc\simeq E$ and
$$
\boxed{r\simeq\frac{7\times10^{12}\,\mathrm{eV}}{ec(9\,\mathrm T)}=2.59\times10^3\,\mathrm m\simeq2.6\,\mathrm{km}.}
$$
The electronvolt-to-joule conversion cancels the elementary-charge factor numerically. This uses external CODATA light speed and charge definitions.<CODATA recommended values of the fundamental physical constants 2014 by National Institute of Standards and Technology>[Vacuum light speed and electronvolt conversion]{ref} If the stated beam energy means total energy, $pc=\sqrt{E^2-m_p^2c^4}$; if it means <kinetic energy>, $pc=\sqrt{T(T+2m_pc^2)}$. Either interpretation gives the quoted radius at the precision of the supplied numbers.
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